Adjustment of radiation patterns utilizing a position sensor

ABSTRACT

A device for a wireless RF link to a remote receiving device can radiate at different radiation patterns in response to detecting a change in the device position. As the device is moved, displaced, or re-positioned, a position sensor in the device detects the change in position and provides position information to a processor. The processor receives the position information from the position sensor, selects an antenna configuration and physical data rate based on the position information, and provides an RF signal associated with the selected antenna configuration through the antenna elements of the selected antenna configuration.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to wireless communications andmore particularly to changing radio frequency (RF) emission patternswith respect to one or more antenna arrays.

2. Description of the Related Art

In wireless communications systems, there is an ever-increasing demandfor higher data throughput and a corresponding drive to reduceinterference that can disrupt data communications. A wireless link in anInstitute of Electrical and Electronic Engineers (IEEE) 802.11 networkmay be susceptible to interference from other access points andstations, other radio transmitting devices, and changes or disturbancesin the wireless link environment between an access point and remotereceiving node. The interference may degrade the wireless link therebyforcing communication at a lower data rate. The interference may, insome instances, be sufficiently strong as to disrupt the wireless linkaltogether.

One solution is to utilize a diversity antenna scheme. In such asolution, a data source and intermediate RF generating device arecoupled to two or more physically separated omnidirectional antennas. Anaccess point may select one of the omnidirectional antennas by which tomaintain a wireless link. Because of the separation between theomnidirectional antennas, each antenna experiences a different signalenvironment and corresponding interference level with respect to thewireless link. A switching network couples the intermediate RFgenerating device and corresponding data source to whichever of theomnidirectional antennas experiences the least interference in thewireless link.

Many methods that provide for switching among antenna configurations,such as diversity antennas, and other methods of controlling antennasegments fail to effectively minimize the interference from other accesspoints, other radio transmitting devices, or disturbances in theenvironment of the wireless link between the access point and the remotereceiving node. Methods for antenna configuration selection aretypically by trial-and-error.

In such a trial-and-error approach, a transmission is made on eachantenna configuration to determine which antenna configuration providesa more effective wireless link as might be measured by a packet errorratio. The trial-and-error approach is inefficient as it generallyrequires transmission on a “bad” antenna configuration to determine theparticularities of the poor quality of that antenna configuration.Further, as the transmitting or receiving device move around, newsources of interference arise to degrade a transmission. Thetrial-and-error approach therefore becomes increasingly inefficient witha large number of antenna configurations and devices that may haveadjustable positions.

FIG. 1 is a block diagram of a wireless device 110 in communication withone or more remote recipient device and as is generally known in theprior art. While not shown, the wireless device 110 of FIG. 1 includesan antenna apparatus, an RF transmitter and/or a receiver, which mayoperate using the 802.11 protocol. The wireless device 110 of FIG. 1 maybe illustrative of a set-top box, a laptop computer, a television, aPCMCIA card, a remote control, a cellular telephone, a handheld gamingdevice, or a remote terminal.

The wireless device 110 may be a handheld device that receives inputthrough an input mechanism configured to be used by a user. The wirelessdevice 110 may then process the input and generates an RF signal. Thegenerated RF signal may then be transmitted to one or more nodes 120,130 and 140 via wireless links. Nodes 120-140 may receive data, transmitdata, or transmit and receive data (i.e., a data transceiver).

Wireless device 110 may also be an access point for communicating withone or more remote receiving nodes over a wireless link as might occurin an 802.11 wireless network. The wireless device 110 may receive datafrom a router connected to the Internet (not shown). The wireless device110 may then convert and wirelessly transmit the data to one or moreremote receiving nodes (e.g., receiving nodes 120-140). The wirelessdevice 110/access point may also receive a wireless transmission fromone of the nodes 120-140 convert the data and allow for transmission ofthat data over the Internet via the aforementioned router. The wirelessdevice 110 may also form a part of a wireless local area network (LAN)that allows for communications among two or more of nodes 120-140. Forexample, node 140, which may be a cellular phone with WiFi capability,may communicate with node 120, which may be a laptop computer includinga WiFi card or chip with wireless capabilities. Those communications maybe routed through the wireless device 110, which creates the wirelessLAN environment.

Wireless device 110 may be placed in different positions on a wall,desk, or in conjunction with another structure. The radiation patternemitted by the wireless device 110 may then be based on the detectedposition of the device. A radiation pattern that extends in a horizontalmanner from the wireless device 110 may be desirable for a devicemounted flat against a ceiling of room or on a central table-likesurface. Alternatively, when the device is mounted on its side andagainst a wall, a radiation pattern may extend outward in a verticalmanner from the wireless device 110. Such an arrangement may bedesirable if one or more nodes 120-140 are attempting to interact withan access point (wireless device 110) on different floors of a building.

Arranging wireless access points or other wireless devices in such amanner may require the party responsible for installation of wirelessdevice 110 to ensure that it is properly configured for a horizontaland/or vertical wireless transmission. This is especially true withprior art wireless devices and access points that tend to transmit onlyin one-dimension. The particulars of any given radiation patterngenerated by a wireless device may be not be immediately apparent to anindividual charged with creating a wireless network but otherwiselacking extensive knowledge into RF emission patterns. Furtherdifficulties might arise with respect to intermediate arrangements ofthe wireless device (e.g., at a 45 degree angle).

The problems associated with radiation patterns become even moreapparent with respect to mobile devices, especially cellular phones ormobile devices with WiFi capability. Such devices are constantly inmotion and may at one moment be on a horizontal plane with an accesspoint and a few moments later be vertical to the access point. The angleof a mobile device vis-à-vis the access point may change in as a littleas a few seconds as a user may walk around an office or even bring thedevice from their desktop up to their ear as they stand at their desk.

There is a need in the art for adjusting antenna patterns andcorresponding radiation patterns to address the particularities of anygiven wireless environment. Such a solution should take into account notonly causes of interference but also the physical position andconfiguration of the transmitting or receiving device.

SUMMARY OF THE PRESENTLY CLAIMED INVENTION

In a first claimed embodiment, a device for transmitting a radiationsignal is disclosed. An antenna apparatus includes multiple antennaconfigurations, each corresponding to a radiation pattern. A positionsensor in the device detects changes in position of the device. Aprocessor receives the position information from the position sensor toselect an antenna configuration and physical data rate based on theposition information.

In a further claimed embodiment, a device for transmitting a wirelesssignal includes an antenna apparatus, antenna configuration selectionmodule, and tilt sensor. The antenna apparatus may be configured in avariety of configurations corresponding to various radiation patterns.The selection module may select a first configuration of the antennaapparatus and a second configuration the antenna apparatus based on aposition of the wireless device as detected by the tilt sensor.

In a third claimed embodiment, a wireless device for transmitting awireless signal is disclosed. The wireless device includes an antennaapparatus, position sensor, and antenna configuration selection module.Various antenna configurations, each associated with a radiationpattern, are possible with respect to the antenna apparatus. Theposition sensor detects a position of the wireless device whileexecution of the antenna selection modules causes selection of anantenna configuration based on the detected position of the wirelessdevice position.

In a fourth claimed embodiment, a method for adjusting a radiationpattern is disclosed. The method includes select a first antennaconfiguration corresponding to a radiation pattern when a wirelessdevice is in a first position; transmitting an RF signal using the firstconfiguration; detecting a change in the position of the device;selecting a second antenna configuration having a second pattern; andtransmitting an RF signal using the second configuration.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram of a wireless device in communication with oneor more remote recipient devices and as is generally known in the priorart.

FIG. 2 is a block diagram of an exemplary wireless device transmittingan RF signal in different physical positions.

FIG. 3 is a block diagram of an exemplary wireless device, which may beconfigured in different physical positions like that disclosed in FIG.2.

FIG. 4 is a block diagram of an exemplary software layer, interfacelayer and hardware layer of the wireless device of FIG. 3.

FIG. 5 is an exemplary table of transmission control data as may beutilized by the wireless device of FIG. 3.

FIG. 6 is an exemplary method for transmitting data based on thephysical position of a wireless device.

FIG. 7 illustrates an exemplary method for processing feedback at awireless device.

DETAILED DESCRIPTION

A device for a wireless RF link to a remote receiving device includes anantenna apparatus with selectable antenna elements for transmitting andreceiving an RF signal, a signal converter for converting betweenencoded signals and RF signals, a processor for controlling the signalconverter and the antenna apparatus, and a position sensor. As thedevice is moved, displaced, or re-positioned, the position sensordetects a change in position and provides position information to theprocessor. The processor receives the position information from theposition sensor, selects an antenna configuration based on the positioninformation, and selects a physical data rate to maximize datatransmission speed. The processor then provides an encoded signal to thesignal converter and controls the converter and antenna apparatus toprovide an RF signal through the antenna elements of the selectedantenna configuration.

For example, when the device is in a first position in a vertical andupright position, the directional radiation pattern resulting from aselected antenna configuration may extend horizontally andperpendicular. When the wireless device position is changed so that itresides on a side and in a horizontal position (i.e., ninety degreesfrom the previous position), the change in position is detected and asecond antenna configuration having a second radiation pattern. Thesecond radiation pattern may extend through the top of the device. If nochange to the antenna configuration was made in response to the changedposition, the selected antenna configuration would result in a radiationpattern that extends in a vertical position (still perpendicular fromthe sides of the device), and thus a weaker signal in the originaldirection from the horizontal position.

A device RF signal can also be changed due to interference from otherradio transmitting devices detected at the new device position, ordisturbances in the wireless link between the system and the remotereceiving device. The processor may select an antenna configuration witha resulting radiation pattern that minimizes the interference. Theprocessor may select an antenna configuration corresponding to a maximumgain between the system and the remote receiving device. Alternatively,the processor may select an antenna configuration corresponding to lessthan maximal gain, but corresponding to reduced interference in thewireless link. Similarly, the processor may select a physical data ratethat maximizes data transmission speed, referred to herein as aneffective user data rate, over the wireless link to the remote receivingdevice.

FIG. 2 is a block diagram of an exemplary wireless device 210transmitting a signal while in different physical positions. Wirelessdevice 210 may also receive a wireless signal. While not illustrated,the wireless device 210 of FIG. 2 includes selectable antenna elements,a signal converter, a processor, memory, various software elements,which may be stored in memory and executable by a processor, and aposition sensor. In the upright position, wireless device 210 has anantenna configuration having a horizontal radiation pattern whichextends horizontally from a side of device 210.

As wireless device 210 changes position—by approximately ninety degreesfrom the vertical position to the horizontal position in FIG. 2—and isplaced on a side, the change of position being detected by an internalposition sensor, the antenna configuration is adjusted in an accordingfashion and based on the current detected position or the detectedchange of position such that a radiation pattern is generated thatextends outward and from the top of wireless device 210 therebyresulting in a second radiation pattern that extends through space inthe same direction as the first radiation pattern provided by wirelessdevice 210. Had the wireless pattern not been adjusted from the changein physical position of wireless device 210, the radiation pattern wouldin a vertical pattern, which may be of use only to a receiving deviceimmediately above or below the wireless transmitting device 210.

FIG. 3 is a block diagram of an exemplary wireless device 300, which maybe configured in different physical positions like that disclosed inFIG. 2. Wireless device 300 may be any device that can be moved and iscapable of transmitting and receiving a wireless signal. For example,wireless device 300 may be implemented as a cellular phone, personaldigital assistant, gaming controller, a lap top computer, or accesspoint subject to being moved. Wireless device 300 as illustrated in FIG.3 includes processor 310, accelerometer 315, tilt sensor 320, output325, input 330, display 335, memory 340, antenna element selector 345,signal converter 350, antenna elements 355, network connection 360, anddata bus 365.

Processor 310 of FIG. 3 is coupled to a memory 340. Processor 310 may berepresentative of a microcontroller, a microprocessor, or anapplication-specific integrated circuit (ASIC). The processor 310 mayexecute programs stored in memory 340. Memory 340 may also storetransmission control data, which may be retrieved by the processor 310to control selection of the antenna configuration of the antennaapparatus 355 and selection of the physical data rate of the signalconverter 350. Aspects of transmission control, antenna elementselection, data rate and so forth are discussed in greater detail withrespect to FIGS. 4 and 5, below.

Processor 310 of FIG. 3 is further coupled to antenna element selectordevice 345 such coupling occurring via control bus 365. Antenna elementselector device 345 is, in turn, coupled to antenna apparatus 355 toallow selection of individual or groups of antenna elements. Differentcombinations of selected antenna elements may result in differentradiation patterns. Processor 310 controls the antenna element selectordevice 345 to select a radiation pattern corresponding to a givenantenna configuration of antenna apparatus 355.

Processor 310 is also coupled to the signal converter 350 by the controlbus 365. Processor 310 controls signal converter 350 to select aphysical data rate from multiple physical data rates at which the signalconverter 350 converts data bits into RF signals for transmission viathe antenna apparatus 355.

Processor 310 may receive packet data from an external network 360.Received packet data is converted into data corresponding to an 802.11wireless protocol at signal converter 350 (e.g., a radiomodulator/demodulator) at the selected physical data rate. The converteddata is transmitted as an RF transmission via the antenna apparatus 355to a remote node over a wireless link.

Antenna apparatus 110 includes a plurality of individually selectableantenna elements (not shown) within antenna apparatus 355. For example,the antenna apparatus may include two antenna elements, three fourantenna elements, or more than four antenna elements. When selected,each of the antenna elements produces a directional radiation patternwith gain as compared to an omnidirectional antenna. The elements ofantenna apparatus 355 are each either directly coupled to an antennaelement selector 345 or via an intermediate individual antenna element.Antenna element selector 345 selectively couples one or more of theantenna elements to the signal converter 350 for transmitting agenerated RF signal. Various embodiments of the antenna apparatus 355and the antenna element selector device 345 are further described incommonly owned U.S. Pat. Nos. 7,292,198; 7,193,562; and 7,362,280.

Device 300 may include any number of ports or interfaces, which maycorrespond to serial communication architectures like Universal SerialBus (USB), RS-x, FireWire, Ethernet, SCSI, and PCI Express or parallelcommunication architectures such as ATA, HIPPI, IEEE-488, and PCMCIA foroutput devices 325 and input devices 330. Examples of suitable outputdevices include speakers, printers, network interfaces, and monitors.Input devices 330 may include or be coupled to user interfaces such asalpha-numeric keypads and keyboards, or pointing devices such as amouse, a trackball, stylus, or cursor direction keys.

Display system 335 may include a liquid crystal display (LCD) or othersuitable display device. Display system 335 receives textual andgraphical information, and processes the information for output to thedisplay device. Output 325, input 330, display 335 and memory 340 arecoupled to processor 310 via one or more buses 365.

Tilt sensor 320 can measure the tilting in two axes of a referenceplane. Tilt sensor 320 may detect pitch and roll and look angles and maybe used to detect a change of position such as angular tilt and transmita signal indicating the position or tilt to processor 310. Processor 310may then process the signal to select an antenna configuration thatprovides the best coverage signal for the current position of thewireless device 300. Tilt sensor 320 may be implemented as one or morehorizontal, vertical, analog, or digital tilt sensors, and may beimplemented as an electrolytic, mercury, gas bubble liquid, pendulum, orother type of tilt sensor.

For example, tilt sensor 320 may be an electrolytic tilt sensor, whichproduces an electric signal to indicate how much a structure is leaningin reference to gravity. Tilt sensor 320 may, in the context of awireless access point, detect whether device 300 is positioned in ahorizontal position (e.g., flat against a ceiling), in a verticalposition (e.g., against a wall), or in some other position. A tiltsensor may also determinate, in the case of a mobile phone, determinewhether the wireless device 300 is positioned upright or is layingrelatively flat on a surface such as a table and generate a signal usedin the selection of an antenna configuration at antenna apparatus 355and corresponding radiation pattern.

Accelerometer 315 can measure acceleration forces experienced bywireless device 300. These forces may be static such as constant forceof gravity pulling at the device, or dynamic such as a force caused bymoving or vibrating device 300. When an acceleration force is detectedby accelerometer 315, accelerometer 315 can provide a signal toprocessor 310 to report the detected acceleration. Processor 310 canprocess the accelerometer signal to aid in the selection of an antennaconfiguration at antenna apparatus 355 that provides a suitableradiation pattern based on any acceleration or change in the position ofdevice 300. In some cases, though tilt sensor may not detect a changedposition of device 300, accelerometer 315 may detect acceleration indevice 300. In such circumstances, processor 310 may probe for anantenna configuration that provides the best radiation pattern inresponse to the accelerometer signal.

Wireless device 300 may also include a global positioning system (GPS)device. The GPS device may be coupled to processor 310 and able toreceive and process signals received from GPS satellites or other signalsources. The location of wireless device 300 may be determined byestimating the time for the GPS device to receive a signal from sourcesatellites or other signal sources. The determined location can beprovided to processor 310 as a signal by the GPS device. Processor 310can process the GPS device signal to aid in the selection of an antennaconfiguration at antenna apparatus 355 that provides a suitableradiation pattern based on any current position or change in theposition of device 300.

Memory 340 may include programs and instructions for execution byprocessor 310. When executed, the programs may select antennaconfigurations based on a detected position, change in position, orother position information provided by accelerometer 315 and/or tiltsensor 320. Selecting an antenna configuration may include creating atable having transmission parameter control data for each remote node.The table may include link quality metrics for each antennaconfiguration. Some examples of link quality metrics are a successratio, an effective user data rate, a received signal strength indicator(RSSI), and error vector magnitude (EVM).

The success ratio can be calculated as a number of data packets receivedby the particular remote receiving node 130 divided by a number of datapackets transmitted to the remote receiving node 130. The success ratiomay be dependent on the physical data rate used to transmit on theantenna configuration. The table may be sorted by the success ratio, forexample, so that highly successful antenna configurations may bepreferably selected. A success ratio may also be calculated in a similarfashion with respect to data successfully received from a transmittingnode.

FIG. 4 illustrates a block diagram of an exemplary software layer 410,interface layer 460, and hardware layer 470 of the wireless device ofFIG. 3. The software layer 410 and the interface layer 460 includeinstructions executed by processor 310. Hardware layer 470 includeshardware elements of the device 100 described with respect to FIG. 3,such as the processor 310, antenna element selector 345, signalconverter 350, and antenna apparatus 355. Although described as softwareand hardware elements, aspects of the device 300 may be implemented withany combination of software, hardware, and firmware elements.

Software layer 410 of FIG. 4 includes a transmission control selectionmodule 430 and a feedback module 440. The transmission control selectionmodule 430 of FIG. 4 includes an antenna configuration selection module415, position sensor module 420, and probe scheduler 425. The feedbackmodule 440 is communicatively coupled to database 435, which may beintegrated in the feedback module 440. The hardware layer 470 of FIG. 4includes a transmitter 460 and a receiver 465.

The transmission control selection 430 is communicatively linked tofeedback module 440. Transmission control selection 430 communicateswith the interface layer 460 via link 445. The feedback modulecommunicates with the interface layer 460 via link 450. The interfacelayer 460 receives packets via link 455 from software layer 410 andsends the packets to the transmitter 475 in the hardware layer 470. Theinterface layer 460 also receives packets from receiver 465 in thehardware layer 470 and sends the packets to the software layer 410 vialink 445.

The transmission control selection 430 includes software elementsconfigured to select and communicate through the interface layer 460 thecurrent antenna configuration and the current physical data rate basedon the feedback module 440, probe scheduler 425, or position sensormodule 420. The probe scheduler 425 includes software elementsconfigured to determine for the transmission control selection 430 anunused antenna configuration and an unused physical data rate based onpredetermined criteria.

One example of the predetermined criteria is determining an unusedantenna configuration after the interface layer 460 indicates asreceived five consecutive packets. The feedback module 440 includessoftware elements configured to update link quality metrics for eachantenna configuration and each physical data rate based on feedback fromthe interface layer 460. The feedback module 440 is configured tomaintain the link quality metrics in the database 435. The positionsensor module 420 includes software elements that receive and processsignals from accelerometer 315 and tilt sensor 320 (FIG. 3). Theprocessing may include determining whether to initiate selection of anew antenna configuration based on the signals received by positionsensor module 420. The operation of the software layer 410, theinterface layer 460, and the hardware layer 470 are described below withrespect to FIG. 6 and FIG. 7.

An advantage of the device 300 is that transmission control selection430 may select, for example, an antenna configuration for the antennaapparatus 355 that minimizes interference for communicating over thewireless link to the remote receiving node 130 based on feedback (i.e.,direct or indirect) from the receiving node. The interface layer 460indicates whether the remote receiving node received transmitted packetson a particular antenna configuration and physical data rate. Further,transmission selection control 410 may select another antennaconfiguration for communicating over the wireless link to the remotereceiving node 130 based on the feedback, thereby changing the radiationpattern of the antenna apparatus 355 to minimize interference in thewireless link.

The transmission control selection 430 may select the appropriateantenna configuration corresponding to a maximum gain for a wirelesslinks between the device 300 and a remote receiving node 130.Alternatively, transmission control selection 430 may select the antennaconfiguration corresponding to less than maximal gain, but correspondingto reduced interference for the particular position of the device. Afurther advantage is that transmission control selection 430 may selectthe physical data rate that provides the maximum effective user datarate at the remote receiving node 130.

FIG. 5 illustrates an exemplary table 500 of transmission control dataas may be utilized by the wireless device of FIG. 3. The table 500 oftransmission control data may be contained in database 435 and accessedby execution of the various software elements of feedback module 440.Table 500 includes columns of device position, antenna configuration,attempted transmissions, successful transmissions, success ratio andRSSI.

The rows of the table 500 correspond to the multiple antennaconfigurations of the antenna apparatus 355. For example, a table oftransmission control data for the antenna apparatus 355 having fourselectable antenna elements {A, B, C, D}, would have fifteen possibleantenna configurations comprising the set{A|B|C|D|AB|AC|AD|BC|BD|CD|ABC|ABD|ACD|BCD|ABCD}, and up to 15 rows oftable entries.

The table 500 may be kept in the database 435 of FIG. 4 for each of theremote receiving nodes 120-140. Each of the remote receiving nodes120-140 may require different antenna configurations and/or physicaldata rates for optimal performance of each of the wireless links betweenthe device and remote receiving nodes 120-140, therefore multiple table500 s may be kept. For example, if five remote receiving nodes wereassociated with the device 100, the processor 320 would maintain aseparate table 500 for each of the five remote receiving nodes. For easeof discussion, only a single table 500 will be discussed.

The table 500 identifies, for each of several positions for each antennaconfiguration, a number of attempted transmissions and a number ofsuccessful transmissions. Feedback module 440 updates the number ofattempted transmissions for the current antenna configuration afterinterface layer 460 indicates a packet has transmitted to a remotereceiving node. The feedback module 440 updates the number of successfultransmissions after the interface layer 460 indicates the packet isreceived by the remote receiving node. In some embodiments, rather thanupdating the number of attempted transmissions when the device drivertransmits the packet, the feedback module 440 may update the number ofattempted transmissions after the interface layer 460 indicates whetherthe remote receiving node received the packet.

The number of device positions for which transmission control data canbe collected can vary based on device resources, designer preference,and other factors. For example, device positions can be associated withpre-arranged ninety degree intervals, such as flat up, vertical facingup, flat facing down, vertical facing down. Further, the positions canbe created as the device is placed in the position. In this case, thetilt sensor 320 can provide position information to position sensormodule 420, which can in turn provide the position information tofeedback module 440 to be stored in table 500. When position informationis stored in the “device position” column, transmission control data canbe configured for different antenna configurations at the particularposition.

Table 500 also stores a success ratio and a RSSI. Although the successratio and the RSSI are illustrated in the table, other link qualitymetrics may be stored in the table 500, such as voltage standing waveratio (VSWR), signal quality, bit error rate, and error vector magnitude(EVM). The success ratio includes a computation of the number ofsuccessful transmissions divided by the number of attemptedtransmissions.

The RSSI includes an indication of the strength of the incoming(received) signal in the receiver 480 (e.g., as measured on an 802.11ACK packet received from the remote receiving node 120 in response to apacket transmitted to the remote receiving node 120). The RSSI mayprovide a better measurement than the success ratio for differentiatingbetween antenna configurations. The RSSI may provide a better linkquality metric for determining the current antenna configuration wheneach antenna configuration has small values for the number of attemptedtransmissions and the number of successful transmissions.

In one example, if two packets are sent to the remote receiving node 120using two separate antenna configurations and are received, there maynot be enough information based alone on the respective success ratiosto indicate whether one antenna configuration is more reliable. Each ofthe two separate antenna configurations has a success ratio of 100%(e.g., 2 attempted transmissions over 2 successful transmissions). TheRSSI may provide a more precise link quality metric. If one antennaconfiguration has the RSSI value of 110 and the other antennaconfiguration has the RSSI value of 115, for example, then the antennaconfiguration with the stronger RSSI would potentially provide a morestable wireless link.

FIG. 6 is an exemplary method for transmitting data based on thephysical position of a wireless device. Feedback module 440 mayinitialize the number of attempted transmissions and successfultransmissions in table 500 to be zero. In some embodiments, the feedbackmodule 440 may determine alternative initialization values for the table500. For example, the feedback module 440 may determine initializationvalues for an antenna configuration that provides a substantiallyomnidirectional radiation pattern. The initialization values for theantenna configuration may be a high value for the success ratio or theRSSI to force transmission control selection 430 to select the antennaconfiguration for the interface layer 460.

In step 610, packets are received for transmission using antennaelements of antenna apparatus 355. The packets can be received from overnetwork 360 from another wireless device or a wired network, throughinput 330, or with respect to data in memory 340 (FIG. 3). The packetsmay be encoded and converted to RF format by signal converter 350. Theconverted packets can be provided to interface layer 460.

A decision is made as to whether a change in device position is detectedat step 620. The position change may be detected by tilt sensor 320,accelerometer 315, or a GPS device. Tilt sensor 320 in a wireless routerdevice 300 may detect that the device has been moved from a verticalposition mounted to a wall to a horizontal position on a table. A tiltsensor within a cellular phone device 300 may detect that the phone ismoved from a horizontal position on a desk to a vertical position suchas when a user picks up the phone to view a phone display. Anaccelerometer may detect that a gaming platform device 300 is beingmoved around and is undergoing dynamic acceleration forces. Either anaccelerometer or a tilt sensor may detect that a laptop device 300 ismoved as a user moves the device to another room. If any of tilt sensor320, accelerometer 315, or GPS device detects a change, the detectingelement will send a signal with position information to position sensormodule 420.

In addition to detecting a change in position, tilt sensor 320 (oranother position sensor) may detect the current position of wirelessdevice 300 without detecting a device position change at step 620. Theposition of wireless device 300 may be detected while wireless device300 is stationary. For example, tilt sensor 320 can detect the wirelessdevice position after the wireless device 300 has been stationary for aperiod of time or after detecting that movement of the wireless device300 has stopped. Tilt sensor 320 may send position informationindicating the current position of the wireless device to positionmodule 420.

The position information may indicate a level of tilt, a measure ofacceleration, data regarding a current position of the device, dataregarding a delta in the position of the device, GPS location data, orsome other information representing motion or a position of the device300. Position sensor module 420 receives the position information andsends a signal to antenna configuration selection module 415 indicatingthe current device position or a device position change occurred.

An antenna configuration for the new device position is selected at step660. The antenna configuration can be selected based on the currentdevice position or a change in detected device position. The antennaconfiguration is selected from the multiple antenna configurations inthe table 500. For example, the transmission control selection 430selects the best ranked antenna configuration for the current positionhaving the highest success ratio. The transmission control selection 430may alternatively select the antenna configuration having the highestRSSI for the current position.

In step 670, transmission control selection 430 selects the currentphysical data rate from the multiple physical data rates provided bysignal converter 120. The multiple physical data rates may be defined asin the IEEE 802.11 specification for wireless networks, including thephysical data rates such as 1 Mbps, 2 Mbps, 5.5 Mbps, and 11 Mbps forIEEE 802.11b. In step 680, the interface layer 460 sends the packet tothe transmitter 460 of the hardware layer 470. The transmitter 460transmits the packet on the current antenna configuration at the currentphysical data rate over the wireless link to a particular remotereceiving node.

Returning to step 620, if transmission control selection 430 determinesthat the position information does not indicate a new current positionor there is no change in the device position, then probe scheduler 425of transmission control selection 430 determines whether to probeanother antenna configuration at step 630. Another antenna configurationcan be probed if the number of packets transmitted using the currentantenna configuration satisfies a threshold number of packets, forexample five packets.

If the probe scheduler 425 determines not to perform a probe at step630, transmission control selection 430 selects the current antennaconfiguration for antenna apparatus 355 from the multiple antennaconfigurations in the table 500 in step 650. For example, transmissioncontrol selection 430 may select the listed antenna configuration havingthe highest success ratio. In an alternative embodiment, transmissioncontrol selection 430 may select the antenna configuration having thehighest RSSI.

Transmission control selection 430 can also select the current physicaldata rate from the multiple physical data rates provided by the signalconverter 120. The multiple physical data rates may be defined as in theIEEE 802.11 specification. The interface layer 460 sends the packet tothe transmitter 460 of the hardware layer 470. The transmitter 460transmits the packet on the current antenna configuration at the currentphysical data rate over a wireless link to a particular remote receivingnode (e.g., the remote receiving node 120).

Returning to step 630, retransmission of the packet may be a priority ifthe transmitted packet is not confirmed as received by the remotereceiving node 120. The need for retransmission may indicate problems inthe wireless link between the transmitting device and the remotereceiving node. When retransmitting the packet, transmission controlselection 430 attempts to determine the antenna configuration forretransmission and the physical data rate for retransmission that ismost likely to be successful. In step 640, the transmission controlselection 430 selects an antenna configuration for retransmission. Insome embodiments, the transmission control selection 430 selects thenext lower ranked antenna configuration in the table 500. Transmissioncontrol selection 430 may also select a physical data rate forretransmission. The transmitter 460 then transmits the packet in step680.

In some embodiments, transmission control selection 430 selects the samecurrent antenna configuration, but incrementally lowers the physicaldata rate at which the packet is retransmitted to the remote receivingnode 120. The lower physical data rate provides the remote receivingnode 120 more time to obtain a successful reception of the packet. Inother embodiments, for each retransmission, transmission controlselection 430 alternates between selecting the next antennaconfiguration based on the success ratio and the RSSI.

For example, on the first retransmission, transmission control selection430 selects the next lower ranked antenna configuration based on thesuccess ratio. If the interface layer 460 determines that the remotereceiving node 120 did not indicate reception of the packet, interfacelayer 460 will retransmit the packet, and transmission control selection430 will select the next lower ranked antenna configuration based on theRSSI. For each subsequent retransmission to the remote receiving node120, transmission control selection 430 alternates between selectingantenna configurations based on the success ratio and the RSSI.

Referring back to step 630, when a number of consecutive packets aresuccessfully transmitted to and indicated as received by remotereceiving node 120, indicating stability in the wireless link,transmission control selection 430 may determine to perform a probe ofunused antenna configurations. Probing is the temporary changing of thecurrent antenna configuration to one of the unused antennaconfigurations for transmission of a packet. The unused antennaconfiguration is any antenna configuration that is not the currentantenna configuration. Probing allows the feedback module 440 to updatethe values of the table 500 for the unused antenna configurations.Probing consciously and temporarily changes the current antennaconfiguration to ensure that the database 435 is not stale.Additionally, probing allows the device 100 to anticipate changes in thewireless link.

Based on a positive determination to perform a probe by referencing theprobe scheduler 425, transmission control selection 430 in step 640selects an unused antenna configuration. Transmitting on the unusedantenna configuration may result in a higher ranked success ratio thanthe current antenna configuration. Further, transmission controlselection 430 may probe an unused physical data rate. In step 680, thetransmitter 460 transmits the probe packet to the remote receiving node120.

FIG. 7 illustrates an exemplary method for processing feedback at awireless device. The method begins in step 705 after transmission of thepacket, as described with respect to FIG. 6. In step 710, the feedbackmodule 440 increments the number of attempted transmissions 520 for thecurrent antenna configuration. FIG. 7 illustrates an exemplary methodfor processing feedback at a wireless device.

In step 720, the interface layer 460 determines whether the remotereceiving node 120 indicated reception of the transmitted packet. If theremote receiving node 120 indicated reception of the packet, thefeedback module 440 increments the number of successful transmissions530 for the current antenna configuration. In some embodiments, whetherthe remote receiving node 120 indicated reception of the packet or not,the feedback module 440 computes the success ratio for each antennaconfiguration.

As previously discussed with respect to FIG. 5, feedback module 440determines a variety of link quality metrics which allow thetransmission control selection 430 to select an antenna configuration.In step 730, the feedback module 440 may determine the RSSI for eachantenna configuration 510 for the remote receiving node 120. In step735, the feedback module 440 may determine the effective user data ratefor each physical data rate of each antenna configuration.

In step 740, the feedback module 440 ranks each of the antennaconfigurations by the success ratio for each configuration and deviceposition pair. In step 745, the feedback module 440 may also rank theantenna configurations by the RSSI. In step 750, feedback module 440 mayrank each physical data rate of each antenna configuration for theremote receiving node 120 by the effective user data rate. This enablesthe transmission control selection 430 to select a physical data ratethat may have a higher effective user data rate than the currentphysical data rate.

The embodiments disclosed herein are illustrative. Various modificationsor adaptations of the structures and methods described herein may becomeapparent to those skilled in the art. Such modifications, adaptations,and/or variations that rely upon the teachings of the present disclosureand through which these teachings have advanced the art are consideredto be within the spirit and scope of the present invention. Hence, thedescriptions and drawings herein should be limited by reference to thespecific limitations set forth in the claims appended hereto.

1. A wireless device for wirelessly exchanging data in a wireless localarea network, the wireless device comprising: an antenna apparatusassociated with a plurality of antenna configurations, each antennaconfiguration associated with a different radiation pattern; a positionsensor that detects a change in position of the wireless device; amemory storing link quality metrics for each of the plurality of antennaconfigurations; and a processor executes an antenna configurationselection module stored in the memory, the antenna configurationselection module selecting a particular antenna configuration for theantenna apparatus from a set of two or more antenna configurationsassociated with the position change of the wireless device detected bythe position sensor, wherein the particular antenna configuration isselected based on link quality metrics stored in the memory for eachantenna configuration in the set of antenna configurations.
 2. Thewireless device of claim 1, further comprising an antenna elementselector that selects a group of one or more antenna elements in theantenna apparatus to provide the radiation pattern associated with theparticular antenna configuration from the plurality of antennaconfigurations in response to a control signal generated in response tothe execution of the antenna configuration selection module.
 3. Thewireless device of claim 1, wherein the position sensor is a tiltsensor.
 4. The wireless device of claim 1, wherein the position sensoris an accelerometer.
 5. The wireless device of claim 1, wherein theposition sensor is a global positioning system device.
 6. The wirelessdevice of claim 1, wherein the change in position is associated withninety degree orientation change of the wireless device.
 7. The wirelessdevice of claim 1, wherein selecting the particular antennaconfiguration comprises changing from an initial antenna configurationhaving a first radiation pattern to the particular antenna configurationhaving a second radiation pattern different from the first radiationpattern.
 8. The wireless device of claim 1, wherein link quality metricsfor the particular antenna configuration include stored transmissiondata indicating successful transmissions for the particular antennaconfiguration at the changed position.
 9. The wireless device of claim1, further comprising a signal converter that converts an encoded signalto a radio frequency signal.
 10. The wireless device of claim 1, furthercomprising a display device that provides information to a user of thewireless device.
 11. A wireless device for wirelessly exchanging data ina wireless local area network, comprising: an antenna apparatus having aplurality of antenna configurations, each antenna configurationcorresponding to a different radiation pattern; a memory storing linkquality metrics for each of the plurality of antenna configurations; anantenna configuration selection module stored in the memory andexecutable by a processor to select a first antenna configuration forthe antenna apparatus at a first device position; and a tilt sensorconfigured to detect a position change of the wireless device, whereinthe antenna configuration selection module selects a second antennaconfiguration for the antenna apparatus from a set of two or moreantenna configurations associated with a detected second deviceposition, wherein the second device position is selected based on linkquality metrics stored in the memory for each antenna configuration inthe set of antenna configurations.
 12. The wireless device of claim 11,further including a position sensor module stored in the memory andexecutable by the processor to receive and process a signal from thetilt sensor indicating the position of the device.
 13. The wirelessdevice of claim 11, wherein the tilt sensor is configured to detect aposition change from the first device position to the second deviceposition.
 14. The device of claim 11, further including an input devicefor receiving input from a user.
 15. The wireless device of claim 11,wherein the wireless device is a cellular telephone.
 16. The wirelessdevice of claim 11, wherein the wireless device is a laptop computer.17. A wireless device for wirelessly exchanging data in a wireless localarea network, the wireless device comprising: an antenna apparatushaving a plurality of antenna configurations, each antenna configurationassociated with a different radiation pattern a memory storing linkquality metrics for each of the plurality of antenna configurations; aposition sensor configured to detect a position of the wireless device;and an antenna configuration selection module stored in the memory andexecutable by a processor to select a particular antenna configurationfor the antenna apparatus from a set of two or more antennaconfigurations associated with the detected position of the wirelessdevice, wherein the particular antenna configuration is selected basedon link quality metrics stored in the antenna memory for each antennaconfiguration in the set of antenna configurations.
 18. The wirelessdevice of claim 17, the position sensor configured to detect theposition of the wireless device while the wireless device is stationary.19. The wireless device of claim 17, the position sensor configured todetect the position of the wireless device after the wireless deviceposition has changed.
 20. The wireless device of claim 17, the antennaconfiguration selection module selecting a first antenna configurationbased on a first detected position and selecting a second antennaconfiguration based on a second detected position, the plurality ofantenna configurations including the first antenna configuration andsecond antenna configuration.
 21. A method for adjusting a radiationpattern of a device, comprising: selecting a first antenna configurationassociated with a first radiation pattern while the device is at a firstposition; transmitting an RF signal utilizing the first antennaconfiguration; detecting by a sensor that the device position haschanged from the first position to a second position; selecting a secondantenna configuration associated with a second radiation patterndifferent from the first radiation pattern based on the change in deviceposition, wherein the second antenna configuration is selected from aset of two or more antenna configurations associated with the secondposition based on link quality metrics for each antenna configuration inthe set of antenna configurations; and transmitting an RF signalutilizing the second antenna configuration.
 22. The method of claim 21,further including receiving a signal from a tilt sensor, the receivedsignal associated with a change in the position of the device.
 23. Themethod of claim 21, further including accessing a table of antennaconfiguration data associated with device position information.
 24. Themethod of claim 21, further including selecting the antennaconfiguration based on antenna configuration performance data for thesecond position of the device.
 25. A method for adjusting a radiationpattern of a device, comprising: selecting a first antenna configurationassociated with a first radiation pattern while the device is at a firstposition; receiving an RF signal utilizing the first antennaconfiguration; detecting by a sensor that the device position haschanged from the first position to a second position; selecting a secondantenna configuration associated with a second radiation patterndifferent from the first radiation pattern based on the change in deviceposition, wherein the second antenna configuration is selected from aset of two or more antenna configurations associated with the secondposition based on link quality metrics for each antenna configuration inthe set of antenna configurations; and receiving an RF signal utilizingthe second antenna configuration.
 26. The method of claim 25, furtherincluding receiving a signal from a tilt sensor, the received signalassociated with a change in the position of the device.
 27. The methodof claim 25, further including accessing a table of antennaconfiguration data associated with device position information.
 28. Themethod of claim 25, further including selecting the antennaconfiguration based on antenna configuration performance data for thecurrent position of the device.